Track-type work machines, which utilize self-laying endless track undercarriage, have many advantages over wheel type vehicles, including the provisions of lower ground pressure and increased traction. In view of this, track-type work machines can advantageously operate in wet soil areas and in soils having a large sand content. The track-type undercarriage concept has been further enhanced by replacing the heavy metal track chain with an endless flexible inextensible belt arrangement. The belt undercarriage system offers several advantages over the metal track work machines and the wheel type work machines, including higher speed, less maintenance, simplicity of design, and the ability to travel on improved roadways without damage to the road surface. The belted undercarriage system can also be applied to both powered and non-powered machines. In machine applications where the belt is driven through frictional engagement between the drive wheel and the inner surface of the belt, it is important to maintain a constant high tension force between the belt and the drive and idler wheels. In order for the work machine to operate efficiently, it is important that the work machine operator be aware of decreased belt tension.
One type of belted work machine is shown in U.S. Pat. No. 4,923,257, issued to R. J. Purcell on May 8, 1990. This patent describes a plurality of pivoting arms and fluid cylinders for maintaining the tension on the flexible belt. The load being carried by the vehicle adds to the belt tension. Belt alignment is accomplished by adding or removing one or more adjusting shims between bolted connecting joints of pivoting arms which connect to the wheel assemblies.
While the belted trailer machine described in the above noted patent will function quite satisfactory for the purpose intended, nothing is provided to alert the machine operator when the belt tension decreases for one reason or another. The present invention is directed to overcoming one or more of the problems as set forth above.